In 3GPP (3rd Generation Partnership Project), W-CDMA (Wideband Code Division Multiple Access) mode is standardized as a third-generation cellular mobile communication mode and the service is sequentially started (see, e.g., non-patent document 1). One W-CDMA mode is a spread spectrum mode of FDD with 5-MHz radio frequency bandwidth, and radio physical channels are differentiated by spread codes and code-multiplexed for transmission in the same radio frequency bandwidth.
The W-CDMA mode includes a radio link from the mobile station to the base station (hereinafter, uplink) and a radio link from the base station to the mobile station (hereinafter, downlink). The uplink and the downlink include logical channels (Logical Channel) at SAP (Service Access Point) between a layer 3 and a layer 2, transport channels (Transport Channel) for providing service from a layer 1 to the layer 2, and physical channels (Physical Channel) defined as a transmission channel between radio nodes (base station and mobile station) of the layer 1 for implementing transmission through the transport channel with the use of an actual radio transmission path (see, e.g., non-patent document 2).
The physical channels of the downlink of the W-CDMA are a common pilot channel CPICH (Common Pilot Channel), a synchronization channel SCH (Synchronization Channel), a paging indicator channel PICH (Paging Indicator Channel), a primary common control physical channel P-CCPCH (Primary Common Control Physical Channel), a secondary common control physical channel S-CCPCH (Secondary Common Control Physical Channel), a downlink dedicated physical data channel DPDCH (Dedicated Physical Data Channel), a downlink dedicated physical control channel DPCCH (Dedicated Physical Control Channel), an acquisition indicator channel AICH (Acquisition Indicat Channel), etc.
The physical channels of the uplink of the W-CDMA are a physical random access channel PRACH (Physical Random Access Channel), an uplink dedicated physical data channel DPDCH, and an uplink dedicated physical control channel DPCCH.
The high speed downlink packet access HSDPA (High Speed Downlink Packet Access) (non-patent document 3) mode, in which a downlink of the W-CDMA mode is applied to the high speed packet communication, is standardized.
The downlink physical channels of the HSDPA mode are a high-speed physical downlink shared channel HS-PDSCH (High Speed Physical Downlink Shared Channel) and an HS-DSCH-related shared control channel HS-SCCH (HS-DSCH-related Shared Control Channel).
The uplink physical channel of the HSDPA mode is an HS-DSCH-related uplink dedicated physical control channel HS-DPCCH (Dedicated Physical Control Channel for HS-DSCH).
The high-speed physical downlink shared channel HS-PDSCH of the HSDPA mode is a downlink shared channel shared by a plurality of mobile stations and includes a high-speed downlink shared channel HS-DSCH (High-Speed Downlink Shared Channel) of the transport channel for each mobile station. The HS-PDSH is used for transmitting packet data addressed to the mobile stations from a higher-level layer.
The HS-DSCH-related shared control channel HS-SCCH of the HSDPA mode is a downlink shared channel shared by a plurality of mobile stations and transmits to the mobile stations the information necessary for demodulating the high-speed physical downlink shared channel HS-DSCH (modulation mode, spread code) and the information necessary for an error-correcting decoding process and a hybrid automatic repeat request HARQ (Hybrid Automatic Repeat request) process.
The HS-DSCH-related uplink dedicated physical control channel HS-DPCCH is an uplink dedicated control channel and is used for transmitting downlink quality information CQI (Channel Quality Indication) representing a downlink radio propagation path status and ACK/NACK (Acknowledgement/Negative Acknowledgements) that is reception acknowledgement information corresponding to the hybrid automatic repeat request HARQ.
A control channel for each mobile station is transmitted through a dedicated physical control channel or identified by a shared control channel and mobile station identifier (RNTI: Radio Network Temporary ID). The mobile station identifier is 16-bit. For example, the HS-SCCH is code-multiplexed with HS-DSCH. Therefore, the HS-SCCH may be transmitted in a time (three-slot) range used by one mobile station for the HS-DSCH, and the HS-SCCH can sufficiently contain an information amount necessary for controlling the HS-DSCH (spread code, modulation mode, transport block size, HARQ process information, error-correcting decoding process information, mobile-station identifier, etc.,: a total of 37 bits when an encoding rate is 1.0). The mobile-station identifier is included in the error-correcting encoding process procedure to efficiently use a limited number of bits.
On the other hand, the evolution of the third generation radio access (Evolved Universal Terrestrial Radio Access, hereinafter, EUTRA) and the evolution of the third generation radio access network (Evolved Universal Terrestrial Radio Access Network, hereinafter, EUTRAN) are explored. The OFDM (Orthogonal Frequency Division Multiplexing) mode is proposed for the downlink of the EUTRA. The SUTRA technology applied to the OFDM mode is a technology such as adaptive modulation/demodulation error correction mode (AMCS: Adaptive Modulation and Coding Scheme, hereinafter, AMCS mode) based on adaptive radio link control (link adaptation) such as channel coding.
The AMCS mode is a mode of switching radio transmission parameters (hereinafter, AMC mode) such as an error correction mode, an encoding rate of error correction, a data modulation multi-valued number, a code spreading rate (SF: Spreading Factor) of time/frequency axes, and a multi-code multiplexing number depending on the propagation path statuses of the mobile stations to efficiently perform high-speed packet data transmission. For example, with regard to data modulation, the maximum throughput of a communication system can be increased by switching to the multi-valued modulation with higher efficiency such as from the QPSK (Quadrature Phase Shift Keying) modulation to the 8-PSK modulation and the 16-QAM (Quadrature Amplitude Modulation) modulation as the propagation path status is improved.
With regard to disposition of the downlink physical channels and the transport channels in the OFDM mode, a method of multiplexing the physical control channel and the physical data channel in the same frequency band through the spread code multiplexing is proposed for the Spread-OFDM mode (see, e.g., Patent Document 1). In a method proposed for the Non Spread-OFDM mode (e.g., wireless LAN standard 802.16), the resources of the frequency axis (sub-carrier) and the time axis (OFDM symbol) of the OFDM are used to multiplex the channels in time/frequency through the time division multiplexing TDM (Time Division Multiplexing), the frequency division multiplexing FDM (Frequency Division Multiplexing), or a combination of TDM/FDM.
Although the technical information of the EUTRA (see Non-Patent Document 5) describes a configuration of a downlink radio frame, the radio frame is divided in the frequency direction and the time direction, and data for mobile stations are mapped on divided blocks. To perform this data mapping, the base station must transmit allocation information of the mobile stations for the blocks through the mobile station identifier, etc.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-237803
Patent Document 2: Japanese Laid-Open Patent Publication No. 2004-297756
Non-patent Document 1: 3GPP TS 25.211, V6.4.0 (2005-03), Physical channels and mapping of transport channels onto physical channels, http://www.3gpp.org/ftp/Specs/html-info/25-series.htm
Non-patent Document 2: Keiji Tachikawa, “W-CDMA Mobile Communications System”, ISBN4-621-04894-5, P103, P115, etc.
Non-patent Document 3: 3GPP TR (Technical Report) 25.858, and 3GPP documents related to HSDPA specifications, http://www.3gpp.org/ftp/Specs/html-info/25-series.htm
Non-patent Document 4: R1-050705 “Pilot Channel Structure in Evolved UTRA Downlink” 3GPP TSG RAN WG1 #42 on LTE London, UK, Aug. 29-Sep. 2, 2005
Non-patent Document 5: R1-050707 “Physical Channels and Multiplexing in Evolved UTRA Downlink” 3GPP TSG RAN WG1 #42 on LTE London, UK, Aug. 29-Sep. 2, 2005
Non-patent Document 6: R1-050852 “CQI-based Transmission Power Control for Control Channel in Evolved UTRA” 3GPP TSG RAN WG1 #42 on LTE London, UK, Aug. 29-Sep. 2, 2005